Breathing apparatus with pressure reduction warning device



Nov. 18, 1969 K. F. WENNBERG 3,478,740

BREATHING APPARATUS WITH PRESURE REDUCTION WARNING DEVICE Filed Dec. 12,1966 2 Sheets-Sheet 1 INVENTOR KARL F. WENNBERG ATTORNEYS Nbv. 18, 1969K. F. WENNBERG 3,478,740

BREATHING APPARATUS WITH PRESURE REDUCTION WARNING DEVICE Filed Dec. 12,1966 2 Sheets-Sheet 2 INVENTOR KARL F.' WENNBERG BY QQQ, Day/w ATTORNEYSUnited States Patent U.S. Cl. 128146.4 7 Claims ABSTRACT OF THEDISCLOSURE A breathing apparatus having a breathing mask, a pressure gascontainer, a conduit leading from the container with a pressure reducingdevice to the breathing mask, a high pressure valve connected in theconduit, and having a valve chamber with a valve member thereinspringbiased towards a valve seat communicating with the pressure gassource. The valve shaft carrying the valve memher is movable such thatthe opening between the valve member and the valve seat assumes a shortand limited length so that the valve member will close when the pressuregoes below a certain level.

The invention relates to a breathing apparatus having a breathing mask,a pressure gas container, a conduit leading from the container via apressure reducing device to the breathing mask, and a high pressurevalve connected in the conduit between the container and the pressurereducing device and having a valve chamber and, provided in the chamber,a valve member which is spring-biased against a valve seat communicatingwith the pressure gas source for shutting oil the gas supply.

An object of the invention is to warn the wearer of the *breathingapparatus when the pressure in the high pressure container has gone downto a certain level by causing blockage of the gas supply without forcingthe wearer however to take any immediate step to make the supply operateagain.

The invention is characterized by a valve shaft carrying the valvemember and movable with certain play by the movement limitingarrangement, whereby the opening between the valve member and the valveseat only can assume a short and limited length which is fitted in thatway that the valve member will close by getting below a predeterminedgas pressure.

In comparison with prior known devices, the invention has the advantagereferred to above consisting in that the wearer does not haveimmediately to take any steps when the gas supply is cut off, the supplybeing normally reopened when the container pressure acts on the valveand the opening pressure rises, It is therefore characteristic of thedevice that the reduced opening pressure present during gas consumptionbecomes insuflicient, when the container pressure has gone down underthe said level, for keeping the valve opened, whereby a warning signalis given. However, when the container pressure is only slightly belowthe said level, there is an almost immediate return of the valve, sothat the eifect of the warning on the wearer consists only in cuttingoff the latter part of his inhalation. Upon a continuation of theconsumption of gas, the container pressure decreases more, and this cango on down to a lower value of the pressure, during which time howeverthe gas output that is required to cause a warning to be emitted will besmaller and smaller. Finally, no gas output can be obtained at all, butthe valve has to be opened by hand.

Preferably, the apparatus is provided with a catch and 3',4 78,740Patented Nov. 18, 1969 with actuating means for opening the valve andlocking the same in the opened position. It is particularly suitable toconstruct the actuating member in such a way as to be actuated bypulling, since this lessens the danger of unintentional actuation of themember by pushing or the like.

An embodiment of the invention is shown on the drawing, in which:

FIG. 1 is a schematic diagram of a breathing apparatus according to theinvention;

FIG. 2 shows the high pressure valve with the warning device; and

FIG. 3 is a section on the line IIIIII of FIG. 2.

The FIG. 1, 1 is a breathing mask, 2 a breathing regulator having anexhalation valve and an inhalation valve controlled by the breathingpressure. The regulator 2 is supplied via a conduit 3 from a pressureregulator 4. The breathing regulator 2 and the pressure regulator 4together form a pressure reducing device, to which gas is supplied froma pressure gas container 5 via a high pressure valve 6 with a warningdevice, which can be actuated by means of a handle 7.

FIG. 2 shows in detail the construction of the high pressure valve 6. Itcomprises a housing 11, the lower portion 12 of which has a recess intowhich a cylindrical valve chamber 13 is screwed, which is provided withan aperture for a valve shaft 14 at the upper end. Mounted on shaft 14is a valve member 15, which in its lower position seats on a valve seat16, which communicate via a conduit 17 with the pressure gas container5. Around the valve seat 16 there is an aperture which connects with aconduit 18 leading to the pressure regulator 4, The valve member isactuated in the closing direction by a spring 19, the upper end of whichrests on a washer 20. A washer 21 having a sealing ring inserted underit is in contact with the roof of the chamber, and the undersurface ofthe sealing ring has a recess 23.

The valve shaft 14 continues upwardly and is movable with play in anactuating sleeve 24. The play is due to a pin 25 mounted on the shaftwhich engages a hole 26 in the wall of the sleeve 24, which is providedwith a lower widened portion 27 forming an upper and a lower shoulder.Resting on the upper shoulder is a sleeve 28, which causes a downwardlydirected pressure on sleeve 24 by means of a spring 29.

In the lowermost position of sleeve 24 shown in the figure, the widenedportion 27 is surrounded by a catch in the form of a locking disc 30which in the uppermost position of sleeve 24 can engage the lowershoulder of the widened portion 27 and lock sleeve 24 in an upperposition, in which valve member 15 is unseated from seat 16.

Sleeve 24 can be actuated by the pulling of a handle 7 connected tosleeve 24 by means of a flexible stem consisting of a steel wire 32, aspiral 33 and a cover 34 therefor.

FIG. 3 shows the locking disc 30 which is movable in its longitudinaldirection and biased towards its outer locking position by a spring 35.In the free position shown, the widened portion 27 engages the widerportion of an aperture 36 provided in the locking disc. If the widenedportion 27 is moved upwardly, so that the narrower portion of sleeve 24below the same engages aperture 36, looking disc 39 is free to moveoutwardly under the influence of spring 35 to the locking position, inwhich the narrower portion of aperture 36 engages the narrower portionof sleeve 24 and the locking disc engages the undersurface of widenedportion 27 and prevents the latter from being displaced downwardly.

OPERATION When the apparatus is in operation and no high pressure ispresent in conduit 17, the valve is in the position shown in FIG. 2. Ifthe high pressure in conduit 17 is switched on, valve member 15 ispressed upwardly. Owing to the free movement of pin 25 in aperture 26,this can take place even when the actuating sleeve is in the lowerposition.

The opening pressure on the valve is then the container pressureobtained in conduit 17 from the pressure gas source when no gasconsumption takes place. The opening force is predetermined by thecontainer pressure on one hand and on the other hand by the area of thevalve member on which the pressure acts.

When the valve member is unseated, it is influenced in the openingdirection by an opening force which, if no gas consumption takes place,equals the product of the container pressure by the area on which itacts, this being in the embodiment shown in the cross section of shaft14.

If gas consumption takes place however, the opening force is smaller andit then equals the product of the said area by the lower pressure thenobtaining in conduit 17 owing the pressure drop which is present whengas is consumed. There is thus, on the one hand, a higher value of theopening pressure when no gas consumption takes place, on the other handa reduced value during gas consumption. Between these two values thereare obviously also a continuously decreasing series of intermediatevalues for the reduced pressure, these values being lower, the higher isthe gas consumption.

The essential feature of the invention is the movement limitingarrangement of the valve member which, when the container pressure isdoWn to a certain level, causes the reduced opening pressure to beinsuflicient for keeping the valve open against the action of spring 19,whereby the valve closes and cuts off the gas supply. However, thisexposes the valve to the container pressure, and as long as this has notgone too far down, it is sufiicient to re-open the valve. The length ofthe opening between the valve member and the valve seat is fitted inthat way as to make even the most reduce'd opening pressure that canoccur suflicient for keeping the valve open as long as the containerpressure is above a certain level. A suitable value of this level may be40 atrn. for a container having an initial pressure of 300 atm. When thecontainer pressure is down below the said level, a very heavy reductionof the opening pressure is initially required to cause the valve toshut, and the wearer then only has to decrease his consumption slightlyto make the opening pressure suffice for keeping the valve open. Themore the pressure in the container goes down, the smaller is thereduction of the opening pressure relative to the container pressurethat is required for the valve to close, and the consumption must becorrespondingly low to prevent a shutoff from taking place. The wearerhowever can still go on with his occupation, but he does not have accessto the same consumption of air as at a higher container pressure.

As the container pressure gradually approaches a certain lower level, atwhich not even this is sufiicient for opening the valve, the quantity ofair that can be taken becomes gradually smaller. 1

The weare'r can make the warning device inoperative by pulling thehandle 7. Actuating sleeve 24 is then moved to the upper position andlocking disc 30 engages under the lower shoulder of widened portion 27and retains the actuating sleeve in the upper position. Valve 15 is openand can not be closed, and the warning device is inoperative. It can beput in operation again by pushing in the locking disc 30 against theaction of spring 35. Sleeve 24 is then released and the arrangementoperates as described above.

What is claimed is:

1. A Warning device for a breathing'apparatus comprising a container forgas under pressure, a conduit leading from the container via a pressurereducing device to the breathing mask and a high pressure valveconnected in the conduit between the container and the pressure reducingdevice, the high pressure valve having a valve chamber within which isprovided a --valve member, means for spring biasing the valve membertoward a valve seat to close the valve, a valve shaft connected to theside of the valve member opposite from the valve seat and having an areabigger than the area of the valve seat opening, and wherein said valveshaft is slidably mounted in an aperture in thechamber wall and extendsthrough said chamber wall to a point exterior of said chamber.

2. A device according to claim 1 characterized in that the valve shaftis mounted to the chamber wall by a sealing ring and extends into anarea open to the atmosphere surrounding the breathing apparatus.

3; Device according to claim 2 characterized in that a recess is formedin said sealing ring on the surface thereof turned towards the valvemember.

4. Device according to claim 1, characterized by an actuating membermounted on the valve shaft for opening the valve by hand and comprisinga sleeve which is movable in the direction of the valve shaft andengages the same with play.

5. Device according to claim 4, characterized in that the sleeve isspring urged towards the valve seat.

6. Device according to claim 4, characterized in that the actuatingmember comprises a handle connected with the sleeve by a flexible stem.

7. Device according to claim 4 characterized by a locking disc springurged towards the locking position and adapted for locking the actuatingmember in the opening position.

References Cited UNITED STATES PATENTS 2,854,001 9/1958 Humblet 128142.23,028,860 4/1962 Gagnan et al. 128-142.2 3,147,761 9/1964 Lecocq128-142.2

L. W. TRAPP, Primary Examiner

